1. Field of the Invention
The invention relates to a lamp. More particularly, the invention relates to a light emitting diode (LED) lamp capable of withstanding high voltages.
2. Description of the Related Art
An LED is a semiconductor element, and a material of a light emitting chip of the LED mainly includes a compound selected from group III-V chemical elements, such as gallium phosphide (GaP) or gallium arsenide (GaAs). The light emitting principle of the LED lies in the conversion of electric energy into optical energy. Specifically, after a current is applied to the compound semiconductor, the LED releases an excess of energy in a form of light through the combination of electrons and electron holes. Since the luminance of the LED does not result from heat emission or electric discharge, the life span of the LED can reach 100,000 hours or more. Moreover, the LED has the advantages of fast response speed, compact size, low power consumption, low pollution, high reliability, capability for mass production, etc. Therefore, the application of LED is fairly extensive. For instance, the LED can be applied to a mega-size outdoor display board, a traffic light, a mobile phone, a light source of a scanner and facsimile machine, an LED lamp, and so forth.
In the existing LED lamp design, a screw often passes through the LED board and is locked to the lamp holder. In consideration of structural strength and in compliance with safety standard, the screw is made of metal in most cases. The metal screw can pass the safety verification under the U.S. standard. Nonetheless, when the LED undergoes the voltage endurance inspection under the European standard, the high voltage at 4,000 volts is applied to the LED. Since the LED lamp is not equipped with a protection circuit, the LED is likely to be damaged by the high voltage.